intro and GT550K question
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- On the street
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intro and GT550K question
Hi guys, thanks to the info on this board I have my GT550K up and running after years of sitting in a dark corner of the garage. It was an Ebay find and was a crap shoot as far as the condition of the motor.
It starts an idles perfectly now. I'm working on sorting the jetting, I gutted the rotted stock exhaust pipes, welded in dirt bike style baffles wrapped in batting. Sounds great. I install #30 pilots, down a clip position on the needle, and started with #105 mains but now have #100s in there. Everything is working great BUT the bike has a NASTY vibration from idle to about 5K rpms. It sounds like it is coming from the cylinder area. I figure if it was crank related it would have blown up or gotten worse. It's bad, it shakes the bars and can be heard over the exhaust note!
I know it's hard to diagnose from this short description, an ideas I can try/what to check out?
Thanks, Tuna.
It starts an idles perfectly now. I'm working on sorting the jetting, I gutted the rotted stock exhaust pipes, welded in dirt bike style baffles wrapped in batting. Sounds great. I install #30 pilots, down a clip position on the needle, and started with #105 mains but now have #100s in there. Everything is working great BUT the bike has a NASTY vibration from idle to about 5K rpms. It sounds like it is coming from the cylinder area. I figure if it was crank related it would have blown up or gotten worse. It's bad, it shakes the bars and can be heard over the exhaust note!
I know it's hard to diagnose from this short description, an ideas I can try/what to check out?
Thanks, Tuna.
- Coyote
- Moto GP
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Re: intro and GT550K question
Remove the right side engine cover and check for play in the clutch. If the nut came loose, you would get those symptoms. There is a large nut in the center that holds the clutch hub on. Behind that nut there is (or should be) a splined washer. This is meant to be bent down over the nut to keep it from backing off. Maybe the PO had it apart and neglected to put it back in or forgot to bend down the tab.
At any rate, I'm betting the clutch ready to fall off or explode and self destruct.
At any rate, I'm betting the clutch ready to fall off or explode and self destruct.
I was born with nothing and still have most of it left.
.
1978 GS1000C
1976 GT550 ongoing money pit.
.
1978 GS1000C
1976 GT550 ongoing money pit.
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Re: intro and GT550K question
Ok, I'll check that tonight. Someone has been in there, I can see the mauled up hex screws. Thank you.
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Re: intro and GT550K question
Hi, if the clutch checks out OK I would suspect the wrist-pin bearings, if they fail they can make a very harsh, loud rattle and cause vibration. I hope it isn't those, but if it is, they're a pretty easy fix.
If you pull the cylinders, just replace them, check the wrist pins for wear & scoring too.
Keep us posted ...
If you pull the cylinders, just replace them, check the wrist pins for wear & scoring too.
Keep us posted ...
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
- jabcb
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Re: intro and GT550K question
Question for the experts: could this be due to a starter clutch failure?
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Suzuki:
GT750 2x75
GT550 72 & 75
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Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
- gsx1400dave
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Re: intro and GT550K question
Hi,
This maybe the starter clutch as it is a known problem.
Please see attached service bulletins as 1 PDF.
Please email if you need the (very bad quality) originals.
Dave
Southampton UK
GSX1400
GT550 1974, 1975 and 1976
CR250
This maybe the starter clutch as it is a known problem.
Please see attached service bulletins as 1 PDF.
Please email if you need the (very bad quality) originals.
Dave
Southampton UK
GSX1400
GT550 1974, 1975 and 1976
CR250
You do not have the required permissions to view the files attached to this post.
Dave.
GSX1400 K4
GT550 x 3
CR250
"You need only two tools: WD-40 and duct tape. If it doesn't move and it should, use WD-40. If it moves and shouldn't, use the tape. " - Dave Barry, columnist
GSX1400 K4
GT550 x 3
CR250
"You need only two tools: WD-40 and duct tape. If it doesn't move and it should, use WD-40. If it moves and shouldn't, use the tape. " - Dave Barry, columnist
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Re: intro and GT550K question
That looks like a lot of work! I opened the case today and inside looks new. Nobody has tampered with the clutch hub nut. After removing the clutch plates, I can see quite a bit a bit of slop. I'm betting this is pretty normal, and the starter works great. So I think I will move on.gsx1400dave wrote:Hi,
This maybe the starter clutch as it is a known problem.
Please see attached service bulletins as 1 PDF.
Please email if you need the (very bad quality) originals.
Dave
Southampton UK
GSX1400
GT550 1974, 1975 and 1976
CR250
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- On the street
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Re: intro and GT550K question
I will check this out next. I was hoping for something simple! I can see the "might as well.." syndrome kicking in (rings, bearings, etc..) LOL!Craig380 wrote:Hi, if the clutch checks out OK I would suspect the wrist-pin bearings, if they fail they can make a very harsh, loud rattle and cause vibration. I hope it isn't those, but if it is, they're a pretty easy fix.
If you pull the cylinders, just replace them, check the wrist pins for wear & scoring too.
Keep us posted ...
- H2RICK
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Re: intro and GT550K question
You may also want to check your primary drive gear. The J models had problems in this area and just maybe a PO has messed with yours. A loose primary drive gear will rattle and knock like crazy....and, if left, will screw up the end of the crank.
See US Suzuki Service Bulletin #GT-8 here http://www.oldjapanesebikes.com/mraxl_G ... etins.html
See US Suzuki Service Bulletin #GT-8 here http://www.oldjapanesebikes.com/mraxl_G ... etins.html
GT550A Mint & Original
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MBD Sufferer
H2A Semi-Hot Rod Built From A Basket Case
KZ650C2 Mint & Original...mostly
GSF1200SK6 Bandit...My LD Ride
Additional H2 projects In Boxes.....
MBD Sufferer
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- On the street
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Re: intro and GT550K question
Ok I'll re-torque that. Thanks for the advice.H2RICK wrote:You may also want to check your primary drive gear. The J models had problems in this area and just maybe a PO has messed with yours. A loose primary drive gear will rattle and knock like crazy....and, if left, will screw up the end of the crank.
See US Suzuki Service Bulletin #GT-8 here http://www.oldjapanesebikes.com/mraxl_G ... etins.html
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- On the street
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- Joined: Mon Jun 04, 2012 9:57 am
- Country: usa
- Suzuki 2-Strokes: AC50, GT550K, TL1000S, Z1B, G3SS, CB750, R5,
Re: intro and GT550K question
The center piston has quite a bit of fore and aft movment. All the needle bearings seem good and tight. Guess it's piston slap. Tear down begins....
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Re: intro and GT550K question
Before pulling it apart, it's worth double-checking the ignition timing and the carb sync ... if those are not right, the motor WILL vibrate and rattle ...
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
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- On the street
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- Joined: Mon Jun 04, 2012 9:57 am
- Country: usa
- Suzuki 2-Strokes: AC50, GT550K, TL1000S, Z1B, G3SS, CB750, R5,
Re: intro and GT550K question
Yes sir, triple checked the timing, took some doing, but it is spot on. First I used a dial indicator on each piston top. Then fine tuned with a strobe. I used the method of disconnecting one cylinder at a time and getting a perfect 1100rpm idle on each pair. I get a perfect 1700rpm idle, and it settles down right away. I also checked the exhaust temps with an infra-red. All these tips I picked up here on this forum. I'll keep the updates coming......Craig380 wrote:Before pulling it apart, it's worth double-checking the ignition timing and the carb sync ... if those are not right, the motor WILL vibrate and rattle ...
- Allan k
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Re: intro and GT550K question
Mine has the same symptoms... But havent syncronized the carbs yet.
What is the original spec on the idle rpm?
What is the original spec on the idle rpm?
2-strokes are full of speed,
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4-strokes are full of parts!
- Allan k
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Re: intro and GT550K question
How much vibration is acceptable? Mine idles fine But vibrates under 3000rpm... Also in the handlebar is that okay or is it possible to get it All smooth?
2-strokes are full of speed,
4-strokes are full of parts!
4-strokes are full of parts!